Extreme stress turns regular fat into calorie-burning brown fat

With the number of obese Americans now outnumbering the overweight ones, and with men and women having a less than 1% chance of losing a significant amount of weight at all, researchers from The University of Texas Medical Branch at Galveston have made a discovery that could lead to the first universally effective measure for permanent weight loss.

The researchers have discovered, for the first time in humans, that regular white fat can be converted into brown fat—and they believe they have figured out what triggers the change.

Brown fat is a type of tissue that increases metabolism and decreases blood glucose levels—all without you having to alter your physical activity levels. As compared to regular white fat, brown fat cells are smaller, with more mitochondria, and produce more uncoupling protein 1 (UCP1). Unlike other body cells—which convert calories into energy that powers the cell and body—the excess UCP1 means that brown fat only turns calories into heat.

Previous studies have shown that humans have brown fat in small amounts, and that it more or less can be turned on to burn calories (like in colder temperatures); this study has shown that white fat can actually be “browned.”

[Also check out: Drug converts bad white fat to good brown fat in mice.]

The only problem: This process requires severe and prolonged adrenaline-releasing stress.

Don’t try this at home

Severe burn victims are a model of this kind of stress, experiencing extremely heightened adrenaline levels for several weeks following their injury. Thus, the researchers recruited 72 patients who had sustained severe burns on about 50% of their bodies, as well as 19 healthy control participants.

Samples of white fat were extracted from the patients over the course of their recovery, which were measured for metabolic rates and for cell composition. Further, the resting metabolic rates of the patients themselves were measured.

As the patients spent more and more time with elevated adrenaline levels, the researchers found that the white fat became “browner”—which is to say, the molecular and functional characteristics of the white fat grew more and more like that of brown fat.

“Our study provides proof of concept that browning of white fat is possible in humans. The next step is to identify the mechanisms underpinning this effect and then to develop drugs that mimic the burn-induced effect,” said lead author Labros Sidossis, UTMB professor of internal medicine, in a press release.

These results can be found in the journal Cell Metabolism.

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